UV-unwrap cylinder (lightsaber) with extrusions / insets
You might be looking for Follow Active Quads. This is a method of unwrapping (available by default as a menu option after hitting U to unwrap). This will unwrap the mesh based on the last selected quad (4 point polygon).  The effect is to create a totally flat UV map based on that last selected polygon. Usually you use it to (for example) unwrap a sphere to a totally uniform square of polygons.

Otherwise, I would just mark a seam down the entire cylinder (top to bottom) and do a normal unwrap.